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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//
#include "cbase.h"
#include "Portal_DynamicMeshRenderingUtils.h"
#include "iviewrender.h"
extern ConVar mat_wireframe;
int ClipPolyToPlane_LerpTexCoords( PortalMeshPoint_t *inVerts, int vertCount, PortalMeshPoint_t *outVerts, const Vector& normal, float dist, float fOnPlaneEpsilon )
{
vec_t *dists = (vec_t *)stackalloc( sizeof(vec_t) * vertCount * 4 ); //4x vertcount should cover all cases
int *sides = (int *)stackalloc( sizeof(int) * vertCount * 4 );
int counts[3];
vec_t dot;
int i, j;
Vector mid = vec3_origin;
int outCount;
counts[0] = counts[1] = counts[2] = 0;
// determine sides for each point
for ( i = 0; i < vertCount; i++ )
{
dot = DotProduct( inVerts[i].vWorldSpacePosition, normal) - dist;
dists[i] = dot;
if ( dot > fOnPlaneEpsilon )
sides[i] = SIDE_FRONT;
else if ( dot < -fOnPlaneEpsilon )
sides[i] = SIDE_BACK;
else
sides[i] = SIDE_ON;
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
if (!counts[0])
return 0;
if (!counts[1])
{
// Copy to output verts
//for ( i = 0; i < vertCount; i++ )
memcpy( outVerts, inVerts, sizeof( PortalMeshPoint_t ) * vertCount );
return vertCount;
}
outCount = 0;
for ( i = 0; i < vertCount; i++ )
{
if (sides[i] == SIDE_ON)
{
memcpy( &outVerts[outCount], &inVerts[i], sizeof( PortalMeshPoint_t ) );
++outCount;
continue;
}
if (sides[i] == SIDE_FRONT)
{
memcpy( &outVerts[outCount], &inVerts[i], sizeof( PortalMeshPoint_t ) );
++outCount;
}
if (sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
continue;
Vector& p1 = inVerts[i].vWorldSpacePosition;
// generate a split point
int i2 = (i+1)%vertCount;
Vector& p2 = inVerts[i2].vWorldSpacePosition;
dot = dists[i] / (dists[i]-dists[i+1]);
for (j=0 ; j<3 ; j++)
{
mid[j] = p1[j] + dot*(p2[j]-p1[j]);
}
VectorCopy (mid, outVerts[outCount].vWorldSpacePosition);
outVerts[outCount].texCoord.x = inVerts[i].texCoord.x + dot*(inVerts[i2].texCoord.x - inVerts[i].texCoord.x);
outVerts[outCount].texCoord.y = inVerts[i].texCoord.y + dot*(inVerts[i2].texCoord.y - inVerts[i].texCoord.y);
++outCount;
}
return outCount;
}
void RenderPortalMeshConvexPolygon( PortalMeshPoint_t *pVerts, int iVertCount, const IMaterial *pMaterial, void *pBind )
{
CMatRenderContextPtr pRenderContext( materials );
pRenderContext->Bind( (IMaterial *)pMaterial, pBind );
//PortalMeshPoint_t *pMidVerts = (PortalMeshPoint_t *)stackalloc( sizeof( PortalMeshPoint_t ) * iVertCount );
CMeshBuilder meshBuilder;
IMesh* pMesh = pRenderContext->GetDynamicMesh( true );
meshBuilder.Begin( pMesh, MATERIAL_TRIANGLE_STRIP, iVertCount - 2 );
//any convex polygon can be rendered with a triangle strip by starting at a vertex and alternating vertices from each side
int iForwardCounter = 0;
int iReverseCounter = iVertCount - 1; //guaranteed to be >= 2 to start
do
{
PortalMeshPoint_t *pVertex = &pVerts[iForwardCounter];
meshBuilder.Position3fv( &pVertex->vWorldSpacePosition.x );
meshBuilder.TexCoord2fv( 0, &pVertex->texCoord.x );
meshBuilder.AdvanceVertex();
++iForwardCounter;
if( iForwardCounter > iReverseCounter )
break;
pVertex = &pVerts[iReverseCounter];
meshBuilder.Position3fv( &pVertex->vWorldSpacePosition.x );
meshBuilder.TexCoord2fv( 0, &pVertex->texCoord.x );
meshBuilder.AdvanceVertex();
--iReverseCounter;
} while( iForwardCounter <= iReverseCounter );
meshBuilder.End();
pMesh->Draw();
}
void Clip_And_Render_Convex_Polygon( PortalMeshPoint_t *pVerts, int iVertCount, const IMaterial *pMaterial, void *pBind )
{
PortalMeshPoint_t *pInVerts = (PortalMeshPoint_t *)stackalloc( iVertCount * 4 * sizeof( PortalMeshPoint_t ) ); //really only should need 2x points, but I'm paranoid
PortalMeshPoint_t *pOutVerts = (PortalMeshPoint_t *)stackalloc( iVertCount * 4 * sizeof( PortalMeshPoint_t ) );
PortalMeshPoint_t *pTempVerts;
//clip by the viewing frustum
{
VPlane *pFrustum = view->GetFrustum();
//clip by first plane and put output into pInVerts
iVertCount = ClipPolyToPlane_LerpTexCoords( pVerts, iVertCount, pInVerts, pFrustum[0].m_Normal, pFrustum[0].m_Dist, 0.01f );
//clip by other planes and flipflop in and out pointers
for( int i = 1; i != FRUSTUM_NUMPLANES; ++i )
{
if( iVertCount < 3 )
return; //nothing to draw
iVertCount = ClipPolyToPlane_LerpTexCoords( pInVerts, iVertCount, pOutVerts, pFrustum[i].m_Normal, pFrustum[i].m_Dist, 0.01f );
pTempVerts = pInVerts; pInVerts = pOutVerts; pOutVerts = pTempVerts; //swap vertex pointers
}
if( iVertCount < 3 )
return; //nothing to draw
}
CMatRenderContextPtr pRenderContext( materials );
RenderPortalMeshConvexPolygon( pOutVerts, iVertCount, pMaterial, pBind );
if( mat_wireframe.GetBool() )
RenderPortalMeshConvexPolygon( pOutVerts, iVertCount, materials->FindMaterial( "shadertest/wireframe", TEXTURE_GROUP_CLIENT_EFFECTS, false ), pBind );
stackfree( pOutVerts );
stackfree( pInVerts );
}
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